Such evaporator assembly units are used, for example, for evaporative burners in vehicle heaters. The liquid fuel, in general, the fuel that is also used in a vehicle, is fed here into the porous evaporator medium via a feed line arrangement, distributed in this porous evaporator medium by capillary action and optionally under the action of the force of gravity, and then evaporated on the side of the porous evaporator medium exposed towards the evaporation chamber. The air necessary for mixing with the fuel vapor is introduced into a central area of the evaporation chamber via the air introduction shoulder. This leads to a comparatively good mixing of the air introduced and the fuel vapor, so that a combustible mixture can be made available essentially over the entire volume area of the evaporation chamber. This [mixture] is then ignited and burned during the heating operation, and the heat generated during the combustion is then transferred to a heat carrier medium, for example, into air to be introduced into the interior space of a vehicle or into a liquid medium.
Furthermore, such an evaporator assembly unit may also be used to make available a mixture containing fuel or hydrocarbon vapor in a reformer arrangement, which mixture will then be converted into a gas containing hydrogen in a reforming process taking place at a catalytic material. Consequently, the evaporator assembly unit is used to convert a medium, which is fed in at first in the liquid form and contains hydrocarbon, and which may likewise be the fuel used in a vehicle, into a vapor phase in this case as well. It is, of course, also possible when using such an evaporator assembly unit in a reformer arrangement to mix and burn the hydrocarbon vapor generated, for example, during the start phase, with air, which is likewise introduced, in order to make it possible to make available the high temperatures necessary for the start of the reforming process, especially in the area of the catalytic material of the reformer arrangement.